WO2020066668A1 - Film stratifié multicouche - Google Patents

Film stratifié multicouche Download PDF

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Publication number
WO2020066668A1
WO2020066668A1 PCT/JP2019/035948 JP2019035948W WO2020066668A1 WO 2020066668 A1 WO2020066668 A1 WO 2020066668A1 JP 2019035948 W JP2019035948 W JP 2019035948W WO 2020066668 A1 WO2020066668 A1 WO 2020066668A1
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Prior art keywords
layer
monotonically increasing
increasing region
laminated film
thickness
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PCT/JP2019/035948
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English (en)
Japanese (ja)
Inventor
大 中川
庸介 中西
渡部　誉之
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東洋紡フイルムソリューション株式会社
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Priority to CN201980063566.XA priority Critical patent/CN112805601B/zh
Priority to JP2020548441A priority patent/JP7400725B2/ja
Priority to KR1020217009811A priority patent/KR102532479B1/ko
Priority to US17/278,232 priority patent/US12001041B2/en
Publication of WO2020066668A1 publication Critical patent/WO2020066668A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/263—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer having non-uniform thickness
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters
    • G02B5/285—Interference filters comprising deposited thin solid films
    • G02B5/287—Interference filters comprising deposited thin solid films comprising at least one layer of organic material
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/05—5 or more layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/24—All layers being polymeric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/24—All layers being polymeric
    • B32B2250/244—All polymers belonging to those covered by group B32B27/36
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/42—Alternating layers, e.g. ABAB(C), AABBAABB(C)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00—Coating on the layer surface
    • B32B2255/10—Coating on the layer surface on synthetic resin layer or on natural or synthetic rubber layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/416—Reflective
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/42—Polarizing, birefringent, filtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/708—Isotropic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202—LCD, i.e. liquid crystal displays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2551/00—Optical elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2551/00—Optical elements
    • B32B2551/08—Mirrors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G02F1/133536—Reflective polarizers

Definitions

  • the present disclosure relates to a multilayer laminated film capable of widely reflecting light in a visible light region.
  • a multilayer laminated film in which a number of layers having a low refractive index and a number of layers having a high refractive index are alternately laminated can be an optical interference film that selectively reflects or transmits light of a specific wavelength by structural light interference between layers.
  • such a multilayer laminated film reflects light over a wide wavelength range by gradually changing the film thickness of each layer along the thickness direction or by bonding films having different reflection peaks. It can transmit light and can obtain a high reflectance equivalent to a film using metal, and can be used as a metallic glossy film or a reflection mirror.
  • Patent Documents 1 to 4 etc. it is known that by stretching such a multilayer laminated film in one direction, it can be used as a reflective polarizing film that reflects only a specific polarized light component, and can be used as a brightness enhancement member of a liquid crystal display or the like.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 04-268505
  • Patent Document 2 Japanese Patent Application Laid-Open No. 9-506837
  • Patent Document 3 Japanese Patent Application Laid-Open No. 9-506984
  • Patent Document 4 International Patent Publication No. WO 01/47711 Pamphlet
  • the above-mentioned multilayer laminated film may be required to have a high degree of polarization in addition to maintaining a wide reflection wavelength band. Further, in the above-mentioned multilayer laminated film, it is sometimes required that the color tone is uniform. In addition, in the above-described multilayer laminated film, when viewed from an oblique direction, the whole film may appear reddish (colored), and suppression of redness (colored) may be required at the same time. In particular, in a multilayer laminated film for which reduction in size and weight is desired, since the number of layers to be laminated is finite, it is desired to satisfy the above requirements within a limited thickness or weight range. An object of the present disclosure is to provide a multilayer laminated film that has a high degree of polarization, has a uniform tint, and suppresses tint when observed from an oblique direction while maintaining a wide reflection wavelength band. .
  • the first layer has a layer thickness profile capable of reflecting light having a wavelength of 380 to 780 nm by optical interference, and the first layer has an optical thickness having a first monotonically increasing region.
  • the inclination in the 1B monotonically increasing region with respect to the inclination 1A in the 1A monotonically increasing region.
  • the ratio 1B / 1A of 1B is not less than 0.8 and not more than 1.5, and the layer thickness profile at the optical thickness of the second layer has a second monotonically increasing region.
  • Maximum optical thickness is 2 A 2A monotonically increasing region up to 0 nm and a 2B monotonically increasing region having a minimum optical thickness of more than 200 nm, wherein the ratio 2B / 2A of the gradient 2B in the 2B monotonically increasing region to the gradient 2A in the 2A monotonically increasing region is 1.5.
  • ⁇ 2> The multilayer laminated film according to ⁇ 1>, wherein the average optical thickness in the 1A monotonically increasing region is from 65 nm to 85 nm, and the average optical thickness in the 1B monotonically increasing region is from 140 nm to 160 nm.
  • ⁇ 3> The multilayer laminated film according to ⁇ 1> or ⁇ 2>, wherein the average optical thickness in the 2A monotonically increasing region is from 130 nm to 155 nm, and the average optical thickness in the 2B monotonically increasing region is from 250 nm to 290 nm.
  • ⁇ 4> The multilayer laminated film according to any one of ⁇ 1> to ⁇ 3>, wherein an average reflectance in a wavelength region of 380 nm to 780 nm of light polarized parallel to the reflection axis at normal incidence is 85% or more.
  • a multilayer laminated film having a high degree of polarization, a uniform tint, and a low tint when observed from an oblique direction, while maintaining a wide reflection wavelength band.
  • FIG. 1 is a schematic diagram illustrating an example of a layer thickness profile of a multilayer laminated film of the present disclosure. It is a figure showing each transmission spectrum in a transmission axis and a reflection axis of a multilayer lamination film of this indication.
  • a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
  • a multilayer laminated film according to an embodiment of the present disclosure includes a multilayer alternate laminate of a birefringent first layer mainly composed of a first resin and an isotropic second layer mainly composed of a second resin. It can reflect light in a wide wavelength range in the visible light region having a wavelength of 380 to 780 nm due to the light interference effect of the first layer and the second layer. For example, the light can be reflected in the wavelength range of 400 to 760 nm, preferably in the wavelength range of 380 to 780 nm.
  • the term “reflective” means that the average reflectance at a perpendicular incidence of polarized light parallel to such a direction is at least 50% in at least one arbitrary direction in the film plane. From the viewpoint that the multilayer laminated film retains a wide reflection wavelength band, the reflection may be 50% or more as an average reflectance in each wavelength range, preferably 60% or more, more preferably 70% or more, and still more preferably. Is 85% or more.
  • the average reflectance is a value obtained by subtracting the average transmittance at a wavelength of 380 to 780 nm obtained from 100 using a polarizing film measuring device (“VAP7070S” manufactured by JASCO Corporation).
  • “mainly composed of resin” means that the resin accounts for 70% by mass or more of the total mass of each layer in each layer, preferably 80% by mass or more, more preferably 90% by mass or more. .
  • the multilayer alternating laminated body mainly includes a first resin, and has a birefringent first layer having a thickness of 10 to 1000 nm, a second resin, and a second resin. It is preferable to have a structure in which a total of 30 or more isotropic second layers having a thickness of 10 to 1000 nm are alternately laminated in the thickness direction.
  • the resin constituting each layer will be described in detail later, but is not particularly limited as long as a birefringent layer and an isotropic layer can be formed.
  • a thermoplastic resin is preferable from the viewpoint of easy production of a film.
  • the refractive index in the vertical direction, the horizontal direction, and the thickness direction is defined as birefringence when the difference between the maximum and minimum is 0.1 or more, and isotropic when less than 0.1.
  • the multilayer laminated film according to an embodiment of the present disclosure can reflect light in a wide wavelength range by having the first layer and the second layer having various optical thicknesses. This is because the reflection wavelength is caused by the optical thickness of each layer constituting the multilayer laminated film.
  • the reflection wavelength of a multilayer laminated film is represented by the following (formula 1).
  • ⁇ 2 (n1 ⁇ d1 + n2 ⁇ d2) (Equation 1) (In the above formula, ⁇ represents the reflection wavelength (nm), n1 and n2 represent the refractive index of each layer, and d1 and d2 represent the physical thickness (nm) of each layer.)
  • the optical thickness ⁇ M (nm) is represented by the product of the refractive index nk and the physical thickness dk of each layer as shown in (Equation 2) below.
  • the physical thickness obtained from a photograph taken using a transmission electron microscope can be employed.
  • the thickness range in the monotonically increasing region to be described later can be widened, and it can be designed to reflect light in a wide wavelength range.In such a monotonically increasing region, light in a specific wavelength range can be reflected. It is also possible to design such that light outside the specific wavelength range is reflected in the region, and light is reflected as a whole in a wide wavelength range.
  • the first layer and the second layer each have a specific layer thickness profile, thereby maintaining a wide reflection wavelength band, having a high degree of polarization, and having a uniform tint.
  • a specific layer thickness profile thereby maintaining a wide reflection wavelength band, having a high degree of polarization, and having a uniform tint.
  • the layer thickness profile at the optical thickness of the first layer has a first monotonically increasing region, and the first monotonically increasing region has a 1A monotonically increasing region up to a maximum optical thickness of 100 nm and a minimum optical thickness. It is composed of a 1B monotonically increasing region exceeding 100 nm, and a ratio 1B / 1A of a gradient 1B in the 1B monotonically increasing region to a gradient 1A in the 1A monotonically increasing region is 0.8 or more and 1.5 or less.
  • the layer thickness profile at the optical thickness of the second layer has a second monotonically increasing region, wherein the second monotonically increasing region has a 2A monotonically increasing region up to a maximum optical thickness of 200 nm and a minimum optical thickness.
  • FIG. 1 shows a schematic diagram of an example of the layer thickness profile of the multilayer laminated film of the present disclosure, and shows a graph of each transmission spectrum in the transmission axis and the reflection axis of the multilayer laminated film having the layer thickness profile shown in FIG. It is shown in FIG.
  • the ratio 1B / 1A of the gradient 1B in the 1B monotonically increasing region to the gradient 1A in the 1A monotonically increasing region is 1.0
  • the ratio 2B / of the gradient 2B in the 2B monotonically increasing region to the gradient 2A in the 2A monotonically increasing region is 3.0
  • FIG. 2 shows a transmission spectrum (dotted line) on the transmission axis and a transmission spectrum (solid line) on the reflection axis of the multilayer laminated film having the layer thickness profile shown in FIG. The degree of polarization of the multilayer laminated film calculated from the transmission spectrum shown in FIG.
  • the multilayer laminated film of the present disclosure has a reflection wavelength band in a wide range of a wavelength of 380 to 780 nm.
  • the 1A monotonically increasing region having the inclination 1A and the 1B monotonically increasing region having the inclination 1B constituting the first monotonically increasing region have an optical thickness of 100 nm as a boundary, and the ratio 1B / 1A is 0. It is a continuous area that satisfies 0.8 to 1.5.
  • the 2A monotonically increasing region having the inclination 2A and the 2B monotonically increasing region having the inclination 2B constituting the second monotonically increasing region have an optical thickness of 200 nm as a boundary, and the ratio 2B / 2A is more than 1.5 and less than 5.
  • Multilayer laminated film that has a high degree of polarization, has a uniform tint, and has a low tint when observed from oblique directions, without requiring any special equipment expansion and maintaining a wide reflection wavelength band. Can be produced, and it can be produced without changing the number of layers of the multilayer laminated film from existing ones.
  • the inclination of the layer thickness profile is the inclination of a first-order approximation line obtained by the following method. That is, assuming that the inclination of the first-order approximation line of the layer thickness profile in the 1A monotonically increasing region of the first layer is 1A, and the inclination of the first-order approximation line of the layer thickness profile in the 1B monotonically increasing region is 1B, 1B is obtained from the obtained value. / 1A.
  • the inclination of the first-order approximation line of the layer thickness profile in the 2A monotonically increasing region of the second layer is 2A
  • the inclination of the first-order approximation line of the layer thickness profile in the 2B monotonically increasing region is 2B. / 2A.
  • the number of layers can be increased by doubling or the like as described later.
  • the layer thickness profile for one packet may be seen, and
  • One packet can be a multilayer alternating stack.
  • each of the packets can be regarded as a packet, and each packet is divided into an intermediate layer and the like. Can be regarded as different packets.
  • the boundary in the first monotonically increasing region, has an optical thickness of 100 nm, and the inclination in the 1A monotonically increasing region where the optical thickness is small and the inclination in the 1B monotonically increasing region where the optical thickness is large.
  • the ratio in a specific range, it is possible to uniformly increase the reflection intensity around a wavelength of 550 nm where the visibility is high, while widening the wavelength region corresponding to the first monotonically increasing region, and to make the degree of polarization uniform. Can be improved.
  • the inclination ratio (1B / 1A) is larger than 1.5, it becomes difficult to obtain a high degree of polarization.
  • the boundary of the first layer is 150 nm or 200 nm, it tends to be difficult to uniformly adjust the reflection intensity in an arbitrary wavelength region.
  • the boundary in the second monotonically increasing region, is set to an optical thickness of 200 nm, and in the 2B monotonically increasing region, where the optical thickness is large with respect to the inclination in the 2A monotonically increasing region, where the optical thickness is small.
  • the boundary is set to 200 nm, and the reflection intensity can be uniformly adjusted by making the inclination 2A relatively small in relation to the inclinations 2A and 2B.
  • the slope 2B by making the slope 2B relatively large, it is possible to increase the reflection intensity in the target wavelength region by using high-order reflection such as secondary reflection and tertiary reflection while widening the reflection wavelength band. Become.
  • the value of the ratio of 1B / 1A is 0.8 or more and 1.5 or less, for example, the lower limit is set to 0.8, 0.9, 0.95 or 1.00.
  • a mode in which the value is 1.5, 1.4, 1.3, or 1.25, and a mode in which any lower limit and upper limit are combined are preferable. More specifically, an embodiment in the range of 0.9 to 1.4, an embodiment in the range of 0.95 to 1.3, an embodiment in the range of 1.0 to 1.25, and the like are preferable.
  • the value of the ratio of 2B / 2A is more than 1.5 and less than 5, for example, the lower limit is 1.7, 1.9, 2.1, 2.3 or 2.5, and the upper limit is A mode in which 4.75, 4.5, 4.0, 3.75, or 3.5 and a mode in which any lower limit and upper limit are combined is preferable. More specifically, an embodiment in the range of 1.7 to 4.75, an embodiment in the range of 1.9 to 4.5, an embodiment in the range of 2.1 to 4.0, 2.3 to 3 .75, 2.5-3.5, and the like.
  • Such a layer thickness profile can be obtained by adjusting the comb teeth of the feed block.
  • the slope 1A of the 1A monotonically increasing region in the range up to the optical thickness of 100 nm is preferably 0.80 to 1.35, more preferably 0.85 to 1.30, and still more preferably 0. 90 to 1.15.
  • the inclination 1B of the 1B monotonically increasing region in the range from the optical thickness of 100 nm is preferably 0.80 to 1.35, more preferably 1.00 to 1.30, and still more preferably 1.05 to 1.25. is there. By doing so, the effect of the above-described inclination ratio is further improved, and the decrease in the degree of polarization and the tint when observed from an oblique direction can be further suppressed.
  • the slope 2A of the 2A monotonically increasing region up to an optical thickness of 200 nm is preferably 1.00 to 1.60, more preferably 1.05 to 1.50, and further preferably 1. 15 to 1.35.
  • the slope 2B of the 2B monotonically increasing region in the range from the optical thickness of 200 nm is preferably 2.00 to 6.00, more preferably 2.50 to 5.50, and still more preferably 3.00 to 4.50. is there. By doing so, the effect of the above-described inclination ratio is more excellent, and a decrease in the degree of polarization can be further suppressed.
  • the layer on the thinner side of the optical thickness of the 1A monotonically increasing region preferably has an optical thickness (nm) of 40 to 60, more preferably 43 to 57, and even more preferably 46. ⁇ 54.
  • the layer at the end of the 1B monotonically increasing region on the side with the larger optical thickness preferably has an optical thickness of 180 to 220, more preferably 185 to 215, and still more preferably 190 to 210.
  • the optical thickness (nm) of the layer on the thinner side of the 2A monotonically increasing region is preferably 70 to 90, more preferably 74 to 86, and still more preferably 78. ⁇ 82.
  • the layer at the end of the 2B monotonically increasing region on the side with the larger optical thickness preferably has an optical thickness of 295 to 385, more preferably 310 to 370, and still more preferably 325 to 355.
  • the average of the optical thickness of the first layer (hereinafter also referred to as the average optical thickness) may be 65 nm to 85 nm in the 1A monotonically increasing region in the first monotonically increasing region, and may be 140 nm to 160 nm in the 1B monotonically increasing region. preferable. By doing so, the effect of the layer thickness profile of the first layer as described above is more easily exerted, and the effect of suppressing a decrease in the degree of polarization is further improved.
  • the average of the optical thickness of the second layer (hereinafter also referred to as the average optical thickness) is 130 nm to 155 nm in the 2A monotonically increasing region in the second monotonically increasing region, and 250 nm to 290 nm in the 2B monotonically increasing region. Is preferred. By doing so, the effect of the layer thickness profile of the second layer as described above is more easily exerted, and the effect of suppressing the decrease in the degree of polarization is further improved.
  • the average of the optical thickness of the first layer is preferably 67 nm to 83 nm and 143 nm to 157 nm in the 1A monotonically increasing region and the 1B monotonically increasing region, respectively, from the viewpoint of further facilitating the effect. More preferably, they are 69 nm to 81 nm and 146 nm to 154 nm, respectively.
  • the average of the optical thickness of the second layer is preferably 133 nm to 152 nm and 255 nm to 285 nm in the 2A monotonically increasing region and the 2B monotonically increasing region, respectively, from the viewpoint of further facilitating the effect. More preferably, they are 136 nm to 149 nm and 260 nm to 280 nm, respectively.
  • ⁇ monotonically increasing '' is preferably that the thicker layer is thicker than the thinner layer in all of the multilayer alternating laminates in the multilayer laminated film, but is not limited thereto, and What is necessary is just to see a tendency that the thickness increases from the thinner side to the thicker side. More specifically, when the optical thicknesses are numbered from the thinner side to the thicker side, and the thickness is plotted on the vertical axis with the horizontal axis as the horizontal axis, the film thickness tends to increase. When the average value of the film thickness in each equally divided area increases in the direction of increasing the film thickness in the direction in which the film thickness increases, it is determined that the number of layers is monotonically increasing.
  • the first layer and the second layer may be viewed separately, and the monotonic increase of the first layer and the monotonic increase of the second layer may have different slopes.
  • the monotonic increase may be a mode in which the monotonous increase is performed in all the layers from one outermost layer to the other outermost layer in the multilayer alternate laminate, but in the multilayer alternate laminate, the number of layers is 80%.
  • the aspect may be monotonously increasing in a portion of preferably 90% or more, more preferably 95% or more, and the thickness may be constant or decreasing in the other portion. .
  • the first embodiment of the present disclosure is an embodiment in which the area is monotonically increasing in a portion of 100%, but an aspect in which a non-monotonically increasing region is provided on the side where the layer number is small and / or the layer number is large in such a thickness profile. It may be.
  • a region where the above ratio 1B / 1A satisfies 0.8 or more and 1.5 or less is referred to as a first monotonically increasing region.
  • a region where the above ratio 2B / 2A is more than 1.5 and less than 5 is referred to as a second monotonically increasing region.
  • the range of the monotonically increasing region of the first layer and the second layer is 380 to 780 nm due to optical interference as the multilayer alternating laminate. What is necessary is just to have the range which can reflect this light. Further, the range of the monotonically increasing region of the first layer and the second layer may have a width exceeding a range in which light having a wavelength of 380 to 780 nm can be reflected when the multilayer alternating laminate is formed.
  • the first layer that constitutes the multilayer laminated film of one embodiment of the present disclosure is a birefringent layer, that is, the resin that constitutes it (also referred to as the first resin in the present disclosure) has a birefringent property.
  • a layer can be formed.
  • the resin constituting the first layer is preferably an oriented crystalline resin, and particularly preferably, the oriented crystalline resin is polyester.
  • the polyester preferably contains an ethylene terephthalate unit and / or an ethylene naphthalate unit, more preferably an ethylene naphthalate unit in a range of 80 mol% or more and 100 mol% or less based on the repeating unit constituting the polyester. This is preferable because it is easy to form a layer having a higher refractive index, thereby easily increasing the refractive index difference from the second layer.
  • it is the total content.
  • a naphthalenedicarboxylic acid component is contained as a dicarboxylic acid component, and its content is preferably 80 mol% or more and 100 mol% or less based on the dicarboxylic acid component constituting the polyester.
  • the naphthalenedicarboxylic acid component include a 2,6-naphthalenedicarboxylic acid component, a 2,7-naphthalenedicarboxylic acid component, a component derived from a combination thereof, and a derivative component thereof, and in particular, a 2,6-naphthalenedicarboxylic acid component.
  • a preferred example is a naphthalenedicarboxylic acid component or a derivative component thereof.
  • the content of the naphthalenedicarboxylic acid component is preferably 85 mol% or more, more preferably 90 mol% or more, and preferably less than 100 mol%, more preferably 98 mol% or less, and still more preferably 95 mol% or less. It is.
  • the dicarboxylic acid component constituting the polyester of the first layer in addition to the naphthalenedicarboxylic acid component, a terephthalic acid component, an isophthalic acid component, and the like may be further contained as long as the object of the present disclosure is not impaired. It is preferred to contain.
  • the content is preferably in the range of more than 0 mol% and 20 mol% or less.
  • the content of the second dicarboxylic acid component is more preferably at least 2 mol%, further preferably at least 5 mol%, more preferably at most 15 mol%, further preferably at most 10 mol%.
  • the first layer is a layer having a relatively higher refractive index characteristic than the second layer, and the second layer is more than the first layer. It is a layer having relatively low refractive index characteristics, and is preferably stretched in a uniaxial direction.
  • the uniaxial stretching direction is the X direction
  • the direction perpendicular to the X direction in the film plane is the Y direction (also referred to as a non-stretching direction)
  • the direction perpendicular to the film plane is Z.
  • Direction also referred to as a thickness direction).
  • the polyester containing a naphthalenedicarboxylic acid component as a main component as described above for the first layer, it is possible to realize a high birefringence property while exhibiting a high refractive index in the X direction and a high uniaxial orientation.
  • the difference in the refractive index from the second layer in the direction can be increased, which contributes to a high degree of polarization.
  • the content of the naphthalenedicarboxylic acid component is less than the lower limit, the amorphous property tends to increase, and the difference between the refractive index nX in the X direction and the refractive index nY in the Y direction tends to decrease.
  • a P-polarized component in the present disclosure which is defined as a polarized component parallel to an incident surface including a uniaxial stretching direction (X direction) with the film surface being a reflective surface.
  • X direction uniaxial stretching direction
  • the S-polarized light component is defined as a polarized light component that is perpendicular to an incident surface including a uniaxial stretching direction (X direction), with the film surface being a reflective surface in the multilayer laminated film.
  • an ethylene glycol component is used, and its content is preferably 80 mol% or more and 100 mol% or less based on the diol component constituting the polyester. It is more preferably at least 85 mol% and at most 100 mol%, further preferably at least 90 mol% and at most 100 mol%, particularly preferably at least 90 mol% and at most 98 mol%. If the proportion of the diol component is less than the lower limit, the uniaxial orientation described above may be impaired.
  • the diol component constituting the polyester of the first layer in addition to the ethylene glycol component, further contains a trimethylene glycol component, a tetramethylene glycol component, a cyclohexane dimethanol component, a diethylene glycol component, and the like within a range that does not impair the purpose of the present disclosure. Is also good.
  • the melting point of the polyester used for the first layer is preferably in the range of 220 to 290 ° C, more preferably in the range of 230 to 280 ° C, and further preferably in the range of 240 to 270 ° C.
  • the melting point can be determined by measuring with a differential scanning calorimeter (DSC). If the melting point of the polyester exceeds the upper limit, the fluidity of the polyester during melt-extrusion molding is poor, and discharge and the like may be likely to be non-uniform.
  • the melting point is less than the lower limit, the film-forming properties are excellent, but the mechanical properties of the polyester are likely to be impaired, and the refraction when used as a brightness improving member of a liquid crystal display or a reflective polarizing plate. The rate characteristics tend to be difficult to develop.
  • the glass transition temperature (hereinafter sometimes referred to as Tg) of the polyester used for the first layer is preferably from 80 to 120 ° C, more preferably from 82 to 118 ° C, further preferably from 85 to 118 ° C, and particularly preferably. It is in the range of 100-115 ° C. When Tg is in this range, heat resistance and dimensional stability are excellent, and a refractive index characteristic when used as a brightness improving member of a liquid crystal display or a reflective polarizing plate is easily exhibited.
  • the melting point and the glass transition temperature can be adjusted by controlling the type and amount of the copolymerization component, diethylene glycol as a by-product, and the like.
  • the polyester used for the first layer preferably has an intrinsic viscosity of 0.50 to 0.75 dl / g, more preferably 0.55 to 0.72 dl, measured at 35 ° C. using an o-chlorophenol solution. / G, more preferably 0.56 to 0.71 dl / g.
  • the second layer that constitutes the multilayer laminated film of one embodiment of the present disclosure is an isotropic layer, that is, the resin that constitutes the layer (also referred to as the second resin in the present disclosure) is an isotropic layer.
  • a layer can be formed. Therefore, an amorphous resin is preferable as the resin constituting the second layer. Among them, amorphous polyester is preferable. Note that the term “amorphous” here does not exclude that the second layer has an extremely slight crystallinity. Good.
  • a copolymerized polyester As the resin constituting the second layer, a copolymerized polyester is preferable, and particularly, a copolymerized polyester containing a naphthalenedicarboxylic acid component, an ethylene glycol component and a trimethylene glycol component as a copolymer component is preferably used.
  • the naphthalenedicarboxylic acid component include a 2,6-naphthalenedicarboxylic acid component, a 2,7-naphthalenedicarboxylic acid component, a component derived from a combination thereof, and a derivative component thereof.
  • a preferred example is a 6-naphthalenedicarboxylic acid component or a derivative thereof.
  • copolymer component in the present disclosure means any component that constitutes a polyester, and a subcomponent (less than 50 mol% based on the total acid component or the total diol component as a copolymerization amount).
  • the component (A) is not limited to the copolymer component, and may be used including main components (copolymerization amount of 50 mol% or more based on all acid components or all diol components).
  • a polyester having an ethylene naphthalate unit as a main component as the resin of the second layer, and at that time, use a naphthalenedicarboxylic acid component as the resin of the second layer.
  • the use of a copolymerized polyester is preferred because the compatibility with the first layer is increased and the interlayer adhesion with the first layer tends to be improved, and delamination hardly occurs.
  • the diol component preferably contains at least two components of an ethylene glycol component and a trimethylene glycol component.
  • the ethylene glycol component is preferably used as the main diol component from the viewpoint of film forming properties and the like.
  • the copolymerized polyester of the second layer preferably further contains a trimethylene glycol component as a diol component.
  • a trimethylene glycol component as a diol component.
  • Such a naphthalenedicarboxylic acid component is preferably at least 30 mol% and at most 100 mol% of all carboxylic acid components constituting the copolymerized polyester of the second layer, more preferably. Is from 30 mol% to 80 mol%, more preferably from 40 mol% to 70 mol%. Thereby, the adhesion to the first layer can be further increased. If the content of the naphthalenedicarboxylic acid component is less than the lower limit, the adhesion may decrease from the viewpoint of compatibility.
  • the upper limit of the content of the naphthalenedicarboxylic acid component is not particularly limited, but if it is too large, a difference in refractive index from the first layer tends to be difficult to be exhibited.
  • another dicarboxylic acid component may be copolymerized in order to adjust the refractive index relationship with the first layer.
  • the ethylene glycol component is preferably 50 mol% or more and 95 mol% or less, more preferably 50 mol% or more and 90 mol% or less, and still more preferably the total diol component constituting the copolymerized polyester of the second layer. It is 50 mol% or more and 85 mol% or less, particularly preferably 50 mol% or more and 80 mol% or less. This tends to cause a difference in the refractive index between the first layer and the first layer.
  • the trimethylene glycol component is preferably 3 mol% or more and 50 mol% or less, more preferably 5 mol% or more and 40 mol% or less of all diol components constituting the copolymerized polyester of the second layer. , More preferably 10 mol% or more and 40 mol% or less, particularly preferably 10 mol% or more and 30 mol% or less. Thereby, the interlayer adhesion with the first layer can be further increased. In addition, there is a tendency that a difference in refractive index from the first layer is easily expressed. If the content of the trimethylene glycol component is less than the lower limit, it tends to be difficult to ensure interlayer adhesion, and if it exceeds the upper limit, it becomes difficult to obtain a resin having a desired refractive index and glass transition temperature.
  • the second layer according to an embodiment of the present disclosure may include a thermoplastic resin other than the copolymerized polyester in a range of 10% by mass or less based on the mass of the second layer as long as the object of the present disclosure is not impaired. It may be contained as a second polymer component.
  • the copolyester of the second layer described above preferably has a glass transition temperature of 85 ° C or higher, more preferably 90 ° C or higher, and 150 ° C or lower, still more preferably 90 ° C or higher, It is 120 ° C or lower, particularly preferably 93 ° C or higher and 110 ° C or lower. This is more excellent in heat resistance. In addition, there is a tendency that a difference in refractive index from the first layer is easily expressed. When the glass transition temperature of the copolymerized polyester of the second layer is less than the lower limit, sufficient heat resistance may not be obtained.
  • the crystallization of the second layer when a process such as heat treatment at around 90 ° C. is included.
  • the haze increases due to the embrittlement or embrittlement, and the degree of polarization when used as a luminance improving member or a reflective polarizing plate may be accompanied.
  • the polyester of the second layer may have birefringence due to stretching during stretching, and accordingly, the polyester with respect to the first layer in the stretching direction. The rate difference becomes small, and the reflection performance may decrease.
  • amorphous copolyesters are preferable because the haze increase due to crystallization can be extremely excellently suppressed by heat treatment at 90 ° C. for 1000 hours.
  • the term “amorphous” as used herein means that the heat of crystal fusion when the temperature is raised at a rate of 20 ° C./min in DSC is less than 0.1 mJ / mg.
  • the copolymerized polyester of the second layer include (1) a copolymerized polyester containing a 2,6-naphthalenedicarboxylic acid component as a dicarboxylic acid component and an ethylene glycol component and a trimethylene glycol component as a diol component, and (2) Copolymerized polyesters containing a 2,6-naphthalenedicarboxylic acid component and a terephthalic acid component as a dicarboxylic acid component, and an ethylene glycol component and a trimethylene glycol component as a diol component.
  • the copolyester of the second layer preferably has an intrinsic viscosity of 0.50 to 0.70 dl / g, more preferably 0.55 to 0.65 dl, measured at 35 ° C. using an o-chlorophenol solution. / G.
  • the copolymerized polyester used for the second layer has a trimethylene glycol component as a copolymerization component, the film-forming property may be deteriorated, and by setting the intrinsic viscosity of the copolymerized polyester to the above range, the film-forming property is reduced. Can be further enhanced.
  • the intrinsic viscosity when the above-described copolymerized polyester is used as the second layer is preferably higher from the viewpoint of film-forming properties, but the melt viscosity difference from the polyester of the second layer is increased in a range exceeding the upper limit, The thickness of each layer may be uneven.
  • the multilayer laminated film of one embodiment of the present disclosure may have an outermost layer on one or both surfaces.
  • the outermost layer is mainly composed of a resin.
  • “mainly composed of a resin” means that the resin occupies 70% by mass or more of the total mass of the layer in the layer, preferably 80% by mass or more, more preferably 90% by mass or more.
  • the outermost layer is preferably an isotropic layer, and may be the same resin as the second layer from the viewpoint of manufacturing easiness, and is composed of the above-described copolymer polyester of the second layer. Such an embodiment is preferable.
  • the multilayer laminated film of one embodiment of the present disclosure may have an intermediate layer.
  • the intermediate layer may be referred to as an internal thick film layer or the like in the present disclosure, but refers to a thick film layer existing inside the alternately laminated structure of the first layer and the second layer.
  • a thick film means an optically thick film.
  • a thick layer (sometimes referred to as a thickness adjusting layer or a buffer layer) is formed on both sides of the alternately laminated structure in an initial stage of manufacturing a multilayer laminated film, and then the number of layers is increased by doubling.
  • a method is preferably used, in this case, an intermediate layer is formed by laminating two thick layers to each other, and a thick film layer formed inside becomes an intermediate layer and is formed outside. The thicker layer becomes the outermost layer.
  • the intermediate layer preferably has a thickness of, for example, preferably 5 ⁇ m or more, more preferably 100 ⁇ m or less, and more preferably 50 ⁇ m or less.
  • a thickness of the respective layers constituting the first layer and the second layer are uniformly adjusted without affecting the polarizing function. It will be easier.
  • the intermediate layer may have the same composition as any of the first layer and the second layer, or a composition partially including these compositions. Since the thickness of the intermediate layer is large, it does not contribute to the reflection characteristics. On the other hand, since the transmission characteristics may be affected, when particles are included in the layer, the particle diameter and the particle concentration may be selected in consideration of the light transmittance.
  • the thickness of the intermediate layer is less than the lower limit, the layer structure of the multilayer structure may be disturbed, and the reflection performance may be reduced.
  • the thickness of the intermediate layer exceeds the upper limit, the thickness of the entire multilayer laminated film becomes large, and it may be difficult to save space when used as a reflective polarizing plate or a brightness enhancement member of a thin liquid crystal display.
  • the thickness of each intermediate layer is preferably not less than the lower limit of the above range, and the total thickness of the intermediate layers is not more than the upper limit of the above range. It is preferred that
  • the polymer used for the intermediate layer may be a resin different from the first layer or the second layer as long as it can be present in the multilayer structure using the method for producing a multilayer laminated film of the present disclosure.
  • the composition be the same as that of either the first layer or the second layer or a composition partially including these compositions.
  • the method of forming the intermediate layer is not particularly limited, but, for example, a thick layer is provided on both sides of the alternate lamination structure before performing doubling, and it is perpendicular to the alternate lamination direction using a branch block called a layer doubling block.
  • the intermediate layer can be provided in one layer by dividing the substrate into two in the direction and re-laminating them in the alternate laminating direction.
  • a plurality of intermediate layers can be provided by dividing into three and four in the same manner.
  • the multilayer laminated film of one embodiment of the present disclosure can have a coating layer on at least one surface.
  • a coating layer examples include a slippery layer for imparting slipperiness, and a primer layer for imparting adhesion to a prism layer or a diffusion layer.
  • the coating layer contains a binder component, and may contain, for example, particles in order to impart slipperiness. In order to provide easy adhesion, the binder component to be used may be chemically close to the component of the layer to be bonded.
  • the coating solution for forming the coating layer is preferably an aqueous coating solution using water as a solvent from the viewpoint of the environment, but particularly in such a case, the wettability of the coating solution with respect to the multilayer film is reduced.
  • a surfactant can be contained.
  • a functional agent such as a crosslinking agent may be added to increase the strength of the coating layer.
  • the multilayer laminated film according to an embodiment of the present disclosure is configured such that a polymer constituting the first layer and a polymer constituting the second layer are alternately superimposed in a molten state using a multilayer feed block device, for example, in total.
  • An alternate layered structure having 30 or more layers is formed, buffer layers are provided on both sides thereof, and then the alternate layered structure having the buffer layer is divided into, for example, 2 to 4 using an apparatus called layer doubling, and the alternate layer having the buffer layer is divided. It can be obtained by increasing the number of layers by a method of stacking again so that the number of layers (the number of doublings) of the blocks is 2 to 4 times assuming that the stacked configuration is one block. According to such a method, it is possible to obtain a multilayer laminated film having on both sides an intermediate layer in which two buffer layers are laminated inside a multilayer structure and an outermost layer composed of one buffer layer.
  • Such a multilayer structure is laminated so that the thickness of each of the first and second layers has a desired inclined structure. This can be obtained, for example, by changing the interval or length of the slit in the multilayer feed block device. For example, since the first layer and the second layer have different inclination change rates in at least two optical thickness regions, even in the multilayer feed block, the gap between the slits has at least one or more inflection points. And adjust the length.
  • the multilayer unstretched film has at least one axial direction in the machine direction of the film-forming machine or in a direction orthogonal to the film plane (may be referred to as a transverse direction, a width direction, or a TD).
  • the stretching temperature is preferably in the range of the glass transition temperature (Tg) to (Tg + 20) ° C. of the polymer of the first layer.
  • the stretching ratio is preferably 2.0 to 7.0 times, and more preferably 4.5 to 6.5 times. Within this range, the larger the stretching ratio, the smaller the variation in the refractive index in the plane direction of each of the first and second layers due to the thinning by stretching, and the more uniform the optical interference of the multilayer laminated film in the plane direction. And the difference in the refractive index between the first layer and the second layer in the stretching direction becomes large.
  • known stretching methods such as heating stretching by a rod-shaped heater, roll heating stretching, and tenter stretching can be used.From the viewpoint of reduction in scratches due to contact with rolls and stretching speed, tenter stretching is performed. preferable.
  • the stretching process is also performed in a direction (Y direction) orthogonal to the stretching direction in the film plane and the biaxial stretching is performed, depending on the application, if it is desired to provide the reflective polarization characteristics, 1. It is preferable to keep the stretching ratio at about 01 to 1.20 times. If the stretching ratio in the Y direction is further increased, the polarization performance may decrease.
  • the film After the stretching, the film is heat-set at a temperature of (Tg) to (Tg + 30) ° C. and is toe-out (re-stretched) in the stretching direction within a range of 5 to 15%, thereby obtaining an orientation property of the obtained multilayer laminated film.
  • Tg temperature of (Tg) to (Tg + 30) ° C.
  • Tg + 30 temperature of (Tg + 30) ° C.
  • toe-out re-stretched
  • application to the multilayer laminated film can be performed at any stage, but is preferably performed in the production process of the film, for the film before stretching It is preferable to apply by applying.
  • a multilayer laminated film according to one embodiment of the present disclosure is obtained.
  • a biaxially stretched film is preferable.
  • either a sequential biaxial stretching method or a simultaneous biaxial stretching method is used. Is also good.
  • the stretching ratio may be adjusted so that the refractive index and the thickness of each layer of the first layer and the second layer are adjusted so as to exhibit desired reflection characteristics. In consideration of the refractive index, it may be about 2.5 to 6.5 times in both the vertical and horizontal directions.
  • the multilayer laminated film of the present disclosure is particularly preferably used as a brightness enhancement member or a reflective polarizing plate.
  • the multilayer laminated film of the present disclosure by adopting the above-described polymer composition, layer configuration, and orientation, selectively reflects one polarized light component and selectively transmits the polarized light component and the polarized light component in the vertical direction. Performance can be achieved. More specifically, it is a uniaxially stretched embodiment. Utilizing such performance, it can be used as a brightness enhancement member for a liquid crystal display or the like. When used as a brightness enhancing member, light can be reused by transmitting one polarized light component and reflecting the other untransmitted polarized light component to the light source side without absorbing it, and a good brightness improving effect can be obtained. .
  • a curable resin layer such as a prism layer or a diffusion layer may be laminated on at least one surface of the multilayer laminated film of the present disclosure.
  • the curable resin layer is a thermosetting resin layer or an electron beam curable resin layer.
  • these prism layers or diffusion layers can be laminated via a coating layer having a primer function or the like, which is preferable.
  • the multilayer laminated film of the present disclosure is used as a brightness enhancement member, a liquid crystal display device in which a brightness enhancement member is disposed between a light source of a liquid crystal display and a liquid crystal panel including a polarizer / liquid crystal cell / polarizer is provided. Is exemplified.
  • a prism layer or a prism is further provided, it is preferable to dispose the prism layer or the prism on the liquid crystal panel side of the brightness enhancement member.
  • the multilayer laminated film of the present disclosure can be used as a polarizing plate for a liquid crystal display, etc., in combination with an absorbing polarizer or alone.
  • a polarizing plate for a liquid crystal display etc.
  • an absorbing polarizer or alone.
  • P degree of polarization
  • the laminated multilayer film of the present disclosure As a use of the laminated multilayer film of the present disclosure, more specifically, a liquid crystal display in which a first polarizing plate, a liquid crystal cell, and a second polarizing plate composed of the laminated multilayer film of the present disclosure are laminated in this order. No.
  • the multilayer laminated film was cut out in a film length direction of 2 mm and a width direction of 2 cm, fixed in an embedding capsule, and embedded with an epoxy resin (Epomount manufactured by Refinetech Co., Ltd.).
  • the embedded sample was cut perpendicularly in the width direction with a microtome (ULTRACUT UCT manufactured by LEICA) to obtain a thin film section having a thickness of 50 nm.
  • the film was observed and photographed with a transmission electron microscope (Hitachi S-4300) at an acceleration voltage of 100 kV, and the thickness (physical thickness) of each layer was measured from the photograph.
  • the layer existing inside the multilayer structure was defined as the intermediate layer
  • the layer existing in the outermost layer was defined as the outermost layer, and the thickness of each layer was measured.
  • the value of the physical thickness of each layer obtained above and the value of the refractive index (nX) of each layer obtained by the following (2) are used, and these values are substituted into the above (Equation 2) to obtain the optical thickness of each layer.
  • the average optical thickness was determined for each of the range from the thinner end to 100 nm and the range from 100 nm to the thicker end.
  • the average optical thickness was determined for each of the range from the thinner end to 200 nm and the range from 200 nm to the thicker end. It should be noted that whether the first layer or the second layer can be determined according to the mode of the refractive index. If it is difficult, it can be determined based on the electronic state obtained by analysis by NMR or analysis by TEM.
  • the refractive index of the first layer and the second layer of the multilayer laminated film is such that the layer thickness ratio is 1: 1 under the same conditions as the production conditions of the obtained multilayer laminated film.
  • the refractive indices of the first layer and the second layer measured using the two-layer laminated film are determined as the refractive indexes of the first layer and the second layer of the multilayer laminated film, respectively.
  • the first layer, and the second layer the respective refractive indexes (referred to as nX, nY, and nZ) in the stretching direction (X direction), the direction perpendicular thereto (Y direction), and the thickness direction (Z direction), respectively.
  • the refractive index at a wavelength of 633 nm was measured and determined using a Metricon prism coupler, and the refractive index was determined for each of the first layer and the second layer after stretching.
  • the layer on the thinner side and the layer on the thicker side are determined, and a first-order approximation straight line of the layer thickness profile in a range of 100 nm from the edge on the thinner optical thickness side. Is set to 1A, and the inclination of the first-order approximation straight line of the layer thickness profile in the range where the optical thickness exceeds 100 nm to the end on the thick side is set to 1B. Further, in the monotonically increasing region of the second layer, the layer on the thinner side and the layer on the thicker side are determined, and the slope of the first-order approximation straight line of the layer thickness profile in the range of 200 nm from the thinner optical end.
  • the reflection spectrum of the obtained multilayer laminated film was measured using a polarizing film measuring device (“VAP7070S” manufactured by JASCO Corporation). The measurement was performed using a spot diameter adjusting mask ⁇ 1.4 and a deflection angle stage, the incident angle of the measurement light was set to 0 °, and an axis orthogonal to the transmission axis of the multilayer laminated film determined by cross Nicol search (650 nm). The transmittance at each wavelength (referred to as a reflection axis) was measured at a wavelength of 380 to 780 nm at intervals of 5 nm.
  • VAP7070S polarizing film measuring device
  • the average value of the transmittance was taken in the wavelength range of 380 to 780 nm, and the value obtained by subtracting the average transmittance from 100 was taken as the average reflectance of the reflection axis at normal incidence.
  • the average reflectance was 50% or more, it was determined that the light could be reflected on the reflection axis of the measured multilayer laminated film.
  • the average reflectance is 85% or more, preferably 87% or more, more preferably 90% or more.
  • the color of the multilayer laminated film was evaluated by the following method.
  • the average transmittance in the wavelength range of 505 to 555 nm and the average transmittance in the wavelength range of 555 to 605 nm are determined. It can be evaluated that the tint observed from the front direction of the laminated film is uniform. From such a viewpoint, the above-mentioned ratio (average transmittance in a wavelength range of 505 to 555 nm) / (average transmittance in a wavelength range of 555 to 605 nm) is preferably 1.0 ⁇ 0.7, more preferably 1.0 ⁇ 0.7. It is ⁇ 0.5, more preferably 1.0 ⁇ 0.3, and still more preferably 1.0 ⁇ 0.1.
  • the wavelength range of 750 to 850 nm falls within the visible light region (especially the red region) due to the shift of the spectrum to the shorter wavelength side when the film is observed from an oblique direction (direction of incident angle of 45 to 60 degrees). It is a range of wavelengths to be applied. Therefore, when the maximum value of the transmittance is large in such a wavelength range, when the multilayer laminated film is observed from an oblique direction, the coloring of the multilayer laminated film tends to be more remarkable. When the multilayer laminated film is observed from an oblique direction, the coloring is remarkable, that is, the reflection wavelength band is narrow.
  • the maximum value of the transmittance at a wavelength of 750 to 850 nm is preferably 38% or less, more preferably 36% or less, further preferably 34% or less, and further preferably 30% or less.
  • (6) Degree of Polarization Using a polarizing film measurement device (“VAP7070S” manufactured by JASCO Corporation), the visibility correction polarization degree of the obtained multilayer laminated film was measured, and the degree of polarization (P) (unit:%) was measured. did.
  • the measurement was performed using a spot diameter adjusting mask ⁇ 1.4 and a deflection stage, the incident angle of the measuring light was set to 0 °, and the transmission axis of the multilayer laminated film and the transmission axis determined by cross Nicol search (650 nm). Is calculated on the basis of the average transmittance (wavelength range 400 to 800 nm) of each axis orthogonal to.
  • the degree of polarization (P) is preferably at least 75%.
  • optics such as a brightness enhancement member, it is preferably at least 76%, more preferably at least 77%, further preferably at least 78%.
  • polyester A As the polyester for the first layer, transesterification reaction of dimethyl 2,6-naphthalenedicarboxylate, dimethyl terephthalate, and ethylene glycol in the presence of titanium tetrabutoxide is performed, followed by a polycondensation reaction to obtain an acid component. 95% by mole of a 2,6-naphthalenedicarboxylic acid component, 5% by mole of an acid component is a terephthalic acid component, and a glycol component is an ethylene glycol component (intrinsic viscosity 0.64 dl / g) (o-chlorophenol , 35 ° C, hereinafter the same).
  • Polyester B As the polyester for the second layer, 2,6-naphthalenedicarboxylic acid dimethyl, dimethyl terephthalate, and ethylene glycol and trimethylene glycol are subjected to transesterification in the presence of titanium tetrabutoxide, followed by polycondensation. 50 mol% of the acid component is 2,6-naphthalenedicarboxylic acid component, 50 mol% of the acid component is terephthalic acid component, 85 mol% of the glycol component is ethylene glycol component, and 15 mol% of the glycol component is trimethylene glycol. A copolyester (intrinsic viscosity: 0.63 dl / g) as a component was prepared.
  • polyester A was dried at 170 ° C for 5 hours for the first layer
  • polyester B was dried at 85 ° C for 8 hours for the second layer, and then supplied to the first and second extruders, respectively, to 300 ° C.
  • the first layer and the second layer are alternately laminated, and as shown in Table 1.
  • a multi-layer feed block device provided with comb teeth having a layer thickness profile, a total of 275 layers of a melt in a laminated state are formed.
  • the same polyester as the layer polyester was guided to a three-layer feed block, and buffer layers were further laminated on both sides in the laminating direction of the melt in a laminated state of 275 layers (both surface layers being the first layer).
  • the supply amount of the third extruder was adjusted so that the total of the buffer layers on both sides was 47% of the whole.
  • the laminated state is further branched into two layers by a layer doubling block and laminated at a ratio of 1: 1.
  • An unstretched multilayer laminated film having a total number of 553 layers including an intermediate layer in the inside and two outermost layers in the outermost layer is formed. Produced.
  • This unstretched multilayer laminated film was stretched 5.9 times in the width direction at a temperature of 130 ° C.
  • the thickness of the obtained uniaxially stretched multilayer laminated film was 75 ⁇ m.
  • Examples 2 to 8, Comparative Examples 1 to 8 A uniaxially stretched multilayer laminated film was obtained in the same manner as in Example 1, except that the multilayer feed block device used to obtain the layer thickness profile shown in Table 1 was changed.
  • the multilayer laminated film of the example has a high degree of polarization, has a uniform tint, and is observed from an oblique direction, while maintaining a wide reflection wavelength band, as compared with the multilayer laminated film of the comparative example. In this case, a product having a suppressed color tone was obtained.
  • the multilayer laminated film of the present disclosure has a wide reflection wavelength band by appropriately designing the optical thickness of the birefringent layer and the isotropic layer that are alternately laminated. It is possible to realize a high degree of polarization, a uniform tint, and suppression of tint when observed from an oblique direction while holding. Therefore, for example, when used as a brightness enhancement member that requires polarization performance, a high polarization degree in a wide reflection wavelength band, and hue are suppressed, when used as a reflective polarizing plate, a more reliable brightness enhancement member, A polarizing plate for a liquid crystal display and the like can be provided.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Optical Filters (AREA)
  • Laminated Bodies (AREA)

Abstract

Selon la présente invention, le profil d'épaisseur de couche de l'épaisseur optique d'une première couche comporte une première région à augmentation monotone, la première région à augmentation monotone comprenant une région à augmentation monotone de 1A ayant une épaisseur optique maximale inférieure ou égale à 100 nm et une région à augmentation monotone de 1B ayant une épaisseur optique minimale supérieure à 100 nm, et un rapport 1B/1A d'une pente 1B dans la région à augmentation monotone de 1B à une pente 1A dans la région à augmentation monotone de 1A étant supérieur ou égal à 0,8 mais inférieur à 1,5. Le profil d'épaisseur de couche de l'épaisseur optique d'une seconde couche comporte une seconde région à augmentation monotone, la seconde région à augmentation monotone comprenant une région à augmentation monotone de 2A ayant une épaisseur optique maximale inférieure ou égale à 200 nm et une région à augmentation monotone de 2B ayant une épaisseur optique minimale supérieure à 200 nm, et un rapport 2B/2A d'une pente 2B dans la région à augmentation monotone de 2B à une pente 2A dans la région à augmentation monotone de 2A étant supérieur à 1,5 mais inférieur à 5.
PCT/JP2019/035948 2018-09-27 2019-09-12 Film stratifié multicouche WO2020066668A1 (fr)

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KR1020217009811A KR102532479B1 (ko) 2018-09-27 2019-09-12 다층 적층 필름
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021224799A1 (fr) * 2020-05-08 2021-11-11 3M Innovative Properties Company Film optique
JP7400724B2 (ja) 2018-09-27 2023-12-19 東洋紡株式会社 多層積層フィルム
JP7400723B2 (ja) 2018-09-27 2023-12-19 東洋紡株式会社 多層積層フィルム
US12001040B2 (en) 2018-09-27 2024-06-04 Toyobo Co., Ltd Multilayer laminate film

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002509280A (ja) * 1998-01-13 2002-03-26 ミネソタ マイニング アンド マニュファクチャリング カンパニー 急峻な帯域端部を有する光学フィルム
US20140240829A1 (en) * 2011-10-20 2014-08-28 3M Innovative Properties Company Apodized broadband partial reflectors
WO2018013784A2 (fr) * 2016-07-13 2018-01-18 3M Innovative Properties Company Film optique
WO2018052872A1 (fr) * 2016-09-13 2018-03-22 3M Innovative Properties Company Polariseur réfléchissant à paquet unique à profil d'épaisseur taillé pour de faibles nuances de couleurs à angles obliques
WO2018181841A1 (fr) * 2017-03-31 2018-10-04 帝人フィルムソリューション株式会社 Film stratifié multicouche
WO2019163891A1 (fr) * 2018-02-22 2019-08-29 帝人フィルムソリューション株式会社 Film stratifié multicouche

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5486949A (en) 1989-06-20 1996-01-23 The Dow Chemical Company Birefringent interference polarizer
KR100407210B1 (ko) 1993-12-21 2004-05-31 미네소타 마이닝 앤드 매뉴팩춰링 캄파니 반사편광기디스플레이
DE69423651T2 (de) 1993-12-21 2000-09-21 Minnesota Mining & Mfg Mehrschichtiger optischer film
JP3752410B2 (ja) 1999-12-24 2006-03-08 帝人株式会社 多層積層延伸フィルム
US7385763B2 (en) * 2005-04-18 2008-06-10 3M Innovative Properties Company Thick film multilayer reflector with tailored layer thickness profile
CN103890620B (zh) * 2011-10-20 2017-05-17 3M创新有限公司 具有不同光学分组的变迹宽带局部反射器
CN106772708A (zh) * 2016-12-29 2017-05-31 合肥昂宇光电科技有限公司 一种线性梯度厚度结构的聚合物多层光学膜及制作方法
CN110383123B (zh) * 2017-03-06 2022-05-27 3M创新有限公司 高对比度光学膜和包括该光学膜的设备
CN112789529B (zh) 2018-09-27 2023-04-14 东洋纺株式会社 多层层叠膜
US20210349249A1 (en) 2018-09-27 2021-11-11 Toyobo Co., Ltd. Multilayer laminate film

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002509280A (ja) * 1998-01-13 2002-03-26 ミネソタ マイニング アンド マニュファクチャリング カンパニー 急峻な帯域端部を有する光学フィルム
US20140240829A1 (en) * 2011-10-20 2014-08-28 3M Innovative Properties Company Apodized broadband partial reflectors
WO2018013784A2 (fr) * 2016-07-13 2018-01-18 3M Innovative Properties Company Film optique
WO2018052872A1 (fr) * 2016-09-13 2018-03-22 3M Innovative Properties Company Polariseur réfléchissant à paquet unique à profil d'épaisseur taillé pour de faibles nuances de couleurs à angles obliques
WO2018181841A1 (fr) * 2017-03-31 2018-10-04 帝人フィルムソリューション株式会社 Film stratifié multicouche
WO2019163891A1 (fr) * 2018-02-22 2019-08-29 帝人フィルムソリューション株式会社 Film stratifié multicouche

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7400724B2 (ja) 2018-09-27 2023-12-19 東洋紡株式会社 多層積層フィルム
JP7400723B2 (ja) 2018-09-27 2023-12-19 東洋紡株式会社 多層積層フィルム
US12001040B2 (en) 2018-09-27 2024-06-04 Toyobo Co., Ltd Multilayer laminate film
WO2021224799A1 (fr) * 2020-05-08 2021-11-11 3M Innovative Properties Company Film optique

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